A generic term pertaining to any process of correcting a computed, measured, or observed value based on its deviation from the proper or expected value. Various types of error correction are used in data storage and retrieval systems. Many, though not all, of these work by recording some other data on another part of the media or data stream that can be used to check for discrepancies and possibly be used to reconstruct the data in question. Some work by employing sophisticated algorithms to predict data based on readable data immediately before and after the lost data packet.